One of the main problems encountered since the motor vehicle was invented, was that of developing a mechanism which adequately allows the elimination of motion along the entire length of the power train, thereby permitting it to remain stationary although the wheels continue to turn. For example, as relates specifcally to bicycles, upon ceasing to exert pressure upon the pedals, these remain stationary, whereas the wheels continue to turn. It was thus that the mechanism known as a "freely-turning wheel" became known.
These "free-wheel" mechanisms are generally very complicated and are henceforth costly, both as concerns their concept, as well as their manufacture. On the other hand, they do not in fact supply a truly effective freely-turning wheel, due to the fact that they include a series of components which create a constant source of friction, therefore generating a restraining effect. For example, in the case of a free-wheeling mechanism as applied to bicycles in particular, this generally includes a built-in brake, thus incorporating what can be considered as an integrally comprised restraining effect, in fact, this mechanism contains what amounts to three clearly distinguishable restraining effects upon the bearing on which the sprocket turns and to which the chain is coupled: that is, the aforementioned brake; the brake ratchets upon which the brake mechanism itself constantly slides on; and the tension exerted by the chain itself. There is as well, another case of what is known as a free-wheeling mechanism as used on bicycles, which is the back pedal-pressure brake, working together with a free pinion and which presents a built-in restraining mechanism within itself.
In either of the free-wheeling mechanisms mentioned above, no possibility exists of incorporating an optional reverse, inasmuch as braking will occur precisely upon applying the desired reverse motion. Consequently, this would result in an added inconvenience to the aforementioned known mechanisms.
Another inconvenience of the free-wheeling mechanisms as applied on bicycles, is the fact that has been pointed out which results in their complexity of manufacture. The result, therefore, is that should a simple and rapid adaptation be desired in order to convert from a simple single-speed drive into a multiple-speed drive, the conversion is not feasible inasmuch as it is uneconomical.